Derivatives (Changes in Estimated Fair Value Related to Embedded Derivatives) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives gains (losses)	$ (109)	$ 1,684
Net Derivative Gain (Loss) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives gains (losses)	(109)	1,684
Policyholder benefits and claims [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives gains (losses)	$ 15	$ (47)